General Ishii Shiro, mastermind of the Japanese military germ warfare program.

Reconstruction of a Unit 731 laboratory for "living autopsies."

Circle of crosses where prisoners were tied for exposure to aerial bombs containing plague fleas.

Museum theme warning that war makes all people vulnerable to atrocities.

I am at the Unit 731 Museum in northeastern China. This was the research base for Japanese biowarfare atrocities that far exceeded anything that occurred on the European Front in World War II. So why did the officers in charge of this horrific facility not go before the International Military Tribunal in Tokyo in 1948, the eastern equivalent of the Nuremberg Trials in Europe?

Despite our history books stating that the surrender was "unconditional," there was one concession the Allies made at the highest level. We would hold harmless the Japanese Emperor and any members of his extended family. As a result, General MacArthur released some of the most vicious of Japanese generals, including General Asaka, an Imperial "prince," under whose name the "kill all prisoners" order was issued that triggered the Nanjing Massacre.

However, General Ishii Shiro and the staff at Unit 731 were not royalty. Ishii gathered his officers and swore all to absolute lifetime secrecy before he left China for Japan, taking with him vital Unit 731 experimental records and destroying the rest.

Those members of Unit 731 who returned to Japan were never tried as war criminals. The first two American military investigations (Sanders Report in November 1, 1945 and Thompson Report in May 31, 1946) disclosed the development of bacterial bombs and recommended an immunity-for-information deal. The United States was also pursuing biological warfare. Military staff at Fort Detrick were eager to access scientific data that we did not have. But two additional reports (Fell Report in June 20, 1947 and the Hill and Victor Report in December 12, 1947) interrogated Japanese researchers and fully described the human experiments conducted by Unit 731. The last report concluded that the immunity-for-information exchange was important because "Such information could not be obtained in our own laboratories because of scruples attached to human experimentation."

General Douglas MacArthur told Washington that "...additional data, possibly some statements from Ishii probably can be obtained by informing Japanese involved that information will be retained in intelligence channels and will not be employed as War Crimes' evidence." Ishii and his teams that returned to Japan never faced trial. Ishii Shiro would die in bed at the age of 67.

However, the Russian Army had captured 12 members of Unit 731 and put them on trial in December 25-31, 1949 in the industrial city of Khabarovsk. This revealed to the world for the first time the Unit 731 operations: bubonic plague fleas dropped on civilians and inhumane human experimentation. The West dismissed the event as a Communist show trial. However, the Russians also negotiated clemency for information—the 12 Japanese war criminals were eventually released and repatriated to Japan by 1956.

Many of the Japanese doctors who participated in the gruesome live autopsies at Unit 731 went on to rise to high positions in Japan: Governor of Tokyo, the head of Japan's biggest pharmaceutical company, the president of the Japan Medical Association, and the head of the Japan Olympic Committee.

Japanese veterans of Unit 731 erected a memorial tower for their Unit and held reunions. Today, Japan’s right-wing politicians continue to intimidate those who would call for any real apology and suppress detailed textbook discussions of any wartime atrocities. And the Japanese prime minister continues to visit the Yasukuni Shrine that honors 14 Class A war criminals.

Some of the Unit 731 documents sent to the United States and labeled "top secret" were recently de-classified under Defense Secretary Perry, and are now on view at this museum. The U.S. immunity-for-information deal and our Cold War cover-up, along with the Khabarovsk trial occupy additional rooms at this museum. Recent articles in the American Journal of Bioethics in 2006 and 2015 calling for a public U.S. response in this cover-up have gone ignored. And our own world history textbooks remain silent about Unit 731 and the U.S. immunity-for-information deal.

Before I left the Harbin museum, I talked with their staff with the assistance of my colleague from the Ministry of Education. I had used a modern headset that translated the narration of displays into English.This museum provides the headsets in Japanese also.

"Do many Japanese visit this museum?" I asked.

"Yes," was the reply. "Perhaps a dozen a week but more in some seasons. Some bring flowers. And some apologize."

For all of its horrible images, the theme of this museum is not anti-Japanese. This museum stands as a repository of the documents and artifacts of this horrible time of warfare. And it is the same as the theme at the Nanjing War Museum and the conclusion of Iris Chang’s book The Rape of Nanjing: In times of "all out" warfare, any of us could be stripped of humanity and pulled down to unspeakable cruelty, be it torture, waterboarding, or growing and spreading disease among children.

As one Japanese veteran recently stated without remorse: "When you are in war, you must do whatever you need to do to win."

The Unit 731 Museum in Harbin is here to help everyone avoid going down that path again.